Adhesive vent pad for a battery module

ABSTRACT

The present disclosure includes a battery module having a vent path with an exit port. The battery module also includes a vent pad disposed within the vent path and blocking at least a portion of the exit port, coupled to a boundary surface of the exit port via an adhesive layer between the vent pad and the boundary surface, and configured to enable venting through the exit port by separating from the boundary surface along the adhesive layer in response to a pressure against the vent pad exceeding a venting pressure threshold of the battery module.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of U.S.Provisional Application Ser. No. 62/100,001, filed Jan. 5, 2015,entitled “MECHANICAL AND ELECTRICAL ASPECTS OF LITHIUM ION BATTERYMODULE WITH VERTICAL AND HORIZONTAL CONFIGURATIONS,” which is herebyincorporated by reference in its entirety for all purposes.

BACKGROUND

The present disclosure relates generally to the field of batteries andbattery modules. More specifically, the present disclosure relates to anadhesive vent pad for enabling venting from a battery module.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described below. This discussion is believed to be helpful inproviding the reader with background information to facilitate a betterunderstanding of the various aspects of the present disclosure.Accordingly, it should be understood that these statements are to beread in this light, and not as admissions of prior art.

A vehicle that uses one or more battery systems for providing all or aportion of the motive power for the vehicle can be referred to as anxEV, where the term “xEV” is defined herein to include all of thefollowing vehicles, or any variations or combinations thereof, that useelectric power for all or a portion of their vehicular motive force. Forexample, xEVs include electric vehicles (EVs) that utilize electricpower for all motive force. As will be appreciated by those skilled inthe art, hybrid electric vehicles (HEVs), also considered xEVs, combinean internal combustion engine propulsion system and a battery-poweredelectric propulsion system, such as 48 Volt (V) or 130V systems. Theterm HEV may include any variation of a hybrid electric vehicle. Forexample, full hybrid systems (FHEVs) may provide motive and otherelectrical power to the vehicle using one or more electric motors, usingonly an internal combustion engine, or using both. In contrast, mildhybrid systems (MHEVs) disable the internal combustion engine when thevehicle is idling and utilize a battery system to continue powering theair conditioning unit, radio, or other electronics, as well as torestart the engine when propulsion is desired. The mild hybrid systemmay also apply some level of power assist, during acceleration forexample, to supplement the internal combustion engine. Mild hybrids aretypically 96V to 130V and recover braking energy through a belt or crankintegrated starter generator. Further, a micro-hybrid electric vehicle(mHEV) also uses a “Stop-Start” system similar to the mild hybrids, butthe micro-hybrid systems of a mHEV may or may not supply power assist tothe internal combustion engine and operates at a voltage below 60V. Forthe purposes of the present discussion, it should be noted that mHEVstypically do not technically use electric power provided directly to thecrankshaft or transmission for any portion of the motive force of thevehicle, but an mHEV may still be considered as an xEV since it does useelectric power to supplement a vehicle's power needs when the vehicle isidling with internal combustion engine disabled and recovers brakingenergy through an integrated starter generator. In addition, a plug-inelectric vehicle (PEV) is any vehicle that can be charged from anexternal source of electricity, such as wall sockets, and the energystored in the rechargeable battery packs drives or contributes to drivethe wheels. PEVs are a subcategory of EVs that include all-electric orbattery electric vehicles (BEVs), plug-in hybrid electric vehicles(PHEVs), and electric vehicle conversions of hybrid electric vehiclesand conventional internal combustion engine vehicles.

xEVs as described above may provide a number of advantages as comparedto more traditional gas-powered vehicles using only internal combustionengines and traditional electrical systems, which are typically 12Vsystems powered by a lead acid battery. For example, xEVs may producefewer undesirable emission products and may exhibit greater fuelefficiency as compared to traditional internal combustion vehicles and,in some cases, such xEVs may eliminate the use of gasoline entirely, asis the case of certain types of EVs or PEVs.

As technology continues to evolve, there is a need to provide improvedpower sources, particularly battery modules, for such vehicles. Forexample, in traditional configurations, battery modules may include avent mechanism for venting gases from an inside of the battery module.The vent mechanism may enable venting in response to a pressure increasein the inside of the battery module (e.g., a pressure increase exceedinga venting pressure threshold of the battery module). Unfortunately, sometraditional venting mechanisms for battery modules may be expensive,which drives up the cost of the battery module. Further, sometraditional venting mechanisms may be limited to coarse calibration ofthe venting pressure threshold. Accordingly, it is now recognized thatimproved (e.g., more accurate, economic, and predictable) ventingmechanisms for battery modules are desired.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of certain embodiments and that theseaspects are not intended to limit the scope of this disclosure. Indeed,this disclosure may encompass a variety of aspects that may not be setforth below.

The present disclosure relates to a battery module having a vent pathwith an exit port. The battery module also includes a vent pad disposedwithin the vent path and blocking at least a portion of the exit port,coupled to a boundary surface of the exit port via an adhesive layerbetween the vent pad and the boundary surface, and configured to enableventing through the exit port by separating from the boundary surfacealong the adhesive layer in response to a pressure against the vent padexceeding a venting pressure threshold of the battery module.

The present disclosure also relates a housing of a battery module, wherethe housing includes a cover disposed over an opening in the housing, avent path having an exit port disposed through a wall of the cover, anda vent pad blocking the exit port, coupled to a surface of the wall ofthe cover via an adhesive layer between the vent pad and the surface ofthe wall, and configured to enable venting through the exit port inresponse to a pressure within the vent path and against the vent padexceeding a pressure threshold of the battery module.

The present disclosure also relates to a battery module having a ventpath with an exit port. The battery module also includes a vent padcoupled to a first surface of the battery module through which the exitport extends and disposed over the vent opening. Further, the batterymodule includes a sharp edge facing the vent pad a first distance from aresting position of the vent pad, wherein the vent pad is configured todeflect from the resting position at least the first distance inresponse to a pressure within the vent path and against the vent padexceeding a venting pressure threshold of the battery module, such thatthe sharp edge contacts and opens the vent pad to enable venting throughthe vent opening.

DRAWINGS

Various aspects of this disclosure may be better understood upon readingthe following detailed description and upon reference to the drawings inwhich:

FIG. 1 is a perspective view of a vehicle having a battery systemconfigured in accordance with present embodiments to provide power forvarious components of the vehicle;

FIG. 2 is a cutaway schematic view of an embodiment of the vehicle andthe battery system of FIG. 1;

FIG. 3 is an overhead exploded perspective view of an embodiment of abattery module for use in the vehicle of FIG. 2, in accordance with anaspect of the present disclosure;

FIG. 4 is an overhead perspective view of an embodiment of the batterymodule of FIG. 3, in accordance with an aspect of the presentdisclosure;

FIG. 5 is an overhead perspective view of an embodiment of a cover foruse in the battery module of FIG. 3, in accordance with an aspect of thepresent disclosure;

FIG. 6 is a bottom perspective view of an embodiment of a cover for usein the battery module of FIG. 3, in accordance with an aspect of thepresent disclosure; and

FIG. 7 is a cross-sectional side view of an embodiment of a portion of avent path for use in the battery module of FIG. 3, in accordance with anaspect of the present disclosure;

FIG. 8 is a front view of an embodiment of a portion of a vent path foruse in the battery module of FIG. 3, in accordance with an aspect of thepresent disclosure;

FIG. 9 is a cross-sectional side view of an embodiment of a portion of avent path for use in the battery module of FIG. 3, in accordance with anaspect of the present disclosure;

FIG. 10 is a cross-sectional side view of an embodiment of a portion ofa vent path for use in the battery module of FIG. 3, in accordance withan aspect of the present disclosure; and

FIG. 11 is a schematic view of an embodiment of a portion of a vent pathof a battery module for use in the vehicle of FIG. 2, in accordance withan aspect of the present disclosure.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effortto provide a concise description of these embodiments, not all featuresof an actual implementation are described in the specification. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

The battery systems described herein may be used to provide power tovarious types of electric vehicles (xEVs) and other high voltage energystorage/expending applications (e.g., electrical grid power storagesystems). Such battery systems may include one or more battery modules,each battery module having a number of battery cells (e.g., lithium-ion(Li-ion) electrochemical cells) arranged and electrically interconnectedto provide particular voltages and/or currents useful to power, forexample, one or more components of an xEV. As another example, batterymodules in accordance with present embodiments may be incorporated withor provide power to stationary power systems (e.g., non-automotivesystems).

In accordance with embodiments of the present disclosure, the batterymodule may include a housing (e.g., plastic housing) configured toretain electrochemical cells (e.g., prismatic lithium-ion [Li-ion]electrochemical cells) within an inside of the housing. The housing mayinclude features that seal the inside of the housing from an externalenvironment outside of the housing. The housing may also include a ventpath configured to enable gases to vent from the housing if an internalpressure within the inside of the housing exceeds a venting pressurethreshold of the battery module. Specifically, the vent path may includean exit port having a vent opening. A vent pad (e.g., vent label, ventpatch, adhesive vent label) may be disposed over the vent opening andcoupled to the exit port (e.g., to a surface of the exit port at leastpartially defining the vent path) via an adhesive layer. For example,the adhesive layer may be disposed on the vent pad, and the adhesivelayer of the vent pad may be pressed into the exit port (e.g., to thesurface of the exit port at least partially defining the vent path) withthe vent pad disposed over the vent opening.

During operation of the battery module, the electrochemical cells maythermally expand, causing the pressure on the inside of the housing toincrease. Additionally or alternatively, gases may vent from theindividual electrochemical cells into the inside of the housing, therebycausing the pressure on the inside of the housing to increase. The ventpad (and/or other features of the battery module) may be specificallycalibrated to enable venting of the gases at a venting pressurethreshold. For example, a material or texture of the housing, the ventpad, and/or the adhesive layer may be selected to enable venting of thegases at the venting pressure threshold. Additionally or alternatively,a specific pull-off strength of the adhesive layer (which may corresponddirectly or indirectly to the material or the texture of the adhesivelayer) may be selected to enable venting of the gases at the ventingpressure threshold. Further still, a thickness and/or a cross-sectionalarea of the vent pad, the vent opening, and/or the adhesive layer may beselected to enable venting of the gases at the venting pressurethreshold. These and other features of the vent pad will be described indetail with reference to the figures below.

To help illustrate, FIG. 1 is a perspective view of an embodiment of avehicle 10, which may utilize a regenerative braking system. Althoughthe following discussion is presented in relation to vehicles withregenerative braking systems, the techniques described herein areadaptable to other vehicles that capture/store electrical energy with abattery, which may include electric-powered and gas-powered vehicles.

As discussed above, it would be desirable for a battery system 12 to belargely compatible with traditional vehicle designs. Accordingly, thebattery system 12 may be placed in a location in the vehicle 10 thatwould have housed a traditional battery system. For example, asillustrated, the vehicle 10 may include the battery system 12 positionedsimilarly to a lead-acid battery of a typical combustion-engine vehicle(e.g., under the hood of the vehicle 10). Furthermore, as will bedescribed in more detail below, the battery system 12 may be positionedto facilitate managing temperature of the battery system 12. Forexample, in some embodiments, positioning a battery system 12 under thehood of the vehicle 10 may enable an air duct to channel airflow overthe battery system 12 and cool the battery system 12.

A more detailed view of the battery system 12 is described in FIG. 2. Asdepicted, the battery system 12 includes an energy storage component 13coupled to an ignition system 14, an alternator 15, a vehicle console16, and optionally to an electric motor 17. Generally, the energystorage component 13 may capture/store electrical energy generated inthe vehicle 10 and output electrical energy to power electrical devicesin the vehicle 10.

In other words, the battery system 12 may supply power to components ofthe vehicle's electrical system, which may include radiator coolingfans, climate control systems, electric power steering systems, activesuspension systems, auto park systems, electric oil pumps, electricsuper/turbochargers, electric water pumps, heated windscreen/defrosters,window lift motors, vanity lights, tire pressure monitoring systems,sunroof motor controls, power seats, alarm systems, infotainmentsystems, navigation features, lane departure warning systems, electricparking brakes, external lights, or any combination thereof.Illustratively, in the depicted embodiment, the energy storage component13 supplies power to the vehicle console 16 and the ignition system 14,which may be used to start (e.g., crank) the internal combustion engine18.

Additionally, the energy storage component 13 may capture electricalenergy generated by the alternator 15 and/or the electric motor 17. Insome embodiments, the alternator 15 may generate electrical energy whilethe internal combustion engine 18 is running More specifically, thealternator 15 may convert the mechanical energy produced by the rotationof the internal combustion engine 18 into electrical energy.Additionally or alternatively, when the vehicle 10 includes an electricmotor 17, the electric motor 17 may generate electrical energy byconverting mechanical energy produced by the movement of the vehicle 10(e.g., rotation of the wheels) into electrical energy. Thus, in someembodiments, the energy storage component 13 may capture electricalenergy generated by the alternator 15 and/or the electric motor 17during regenerative braking. As such, the alternator 15 and/or theelectric motor 17 are generally referred to herein as a regenerativebraking system.

To facilitate capturing and supplying electric energy, the energystorage component 13 may be electrically coupled to the vehicle'selectric system via a bus 19. For example, the bus 19 may enable theenergy storage component 13 to receive electrical energy generated bythe alternator 15 and/or the electric motor 17. Additionally, the bus 19may enable the energy storage component 13 to output electrical energyto the ignition system 14 and/or the vehicle console 16. Accordingly,when a 12 volt battery system 12 is used, the bus 19 may carryelectrical power typically between 8-18 volts.

Additionally, as depicted, the energy storage component 13 may includemultiple battery modules. For example, in the depicted embodiment, theenergy storage component 13 includes a lithium ion (e.g., a first)battery module 20 in accordance with present embodiments, and alead-acid (e.g., a second) battery module 22, where each battery module20, 22 includes one or more battery cells. In other embodiments, theenergy storage component 13 may include any number of battery modules.Additionally, although the lithium ion battery module 20 and lead-acidbattery module 22 are depicted adjacent to one another, they may bepositioned in different areas around the vehicle. For example, thelead-acid battery module 22 may be positioned in or about the interiorof the vehicle 10 while the lithium ion battery module 20 may bepositioned under the hood of the vehicle 10.

In some embodiments, the energy storage component 13 may includemultiple battery modules to utilize multiple different batterychemistries. For example, when the lithium ion battery module 20 isused, performance of the battery system 12 may be improved since thelithium ion battery chemistry generally has a higher coulombicefficiency and/or a higher power charge acceptance rate (e.g., highermaximum charge current or charge voltage) than the lead-acid batterychemistry. As such, the capture, storage, and/or distribution efficiencyof the battery system 12 may be improved.

To facilitate controlling the capturing and storing of electricalenergy, the battery system 12 may additionally include a control module24. More specifically, the control module 24 may control operations ofcomponents in the battery system 12, such as relays (e.g., switches)within energy storage component 13, the alternator 15, and/or theelectric motor 17. For example, the control module 24 may regulateamount of electrical energy captured/supplied by each battery module 20or 22 (e.g., to de-rate and re-rate the battery system 12), perform loadbalancing between the battery modules 20 and 22, determine a state ofcharge of each battery module 20 or 22, determine temperature of eachbattery module 20 or 22, control voltage output by the alternator 15and/or the electric motor 17, and the like.

Accordingly, the control unit 24 may include one or more processor 26and one or more memory 28. More specifically, the one or more processor26 may include one or more application specific integrated circuits(ASICs), one or more field programmable gate arrays (FPGAs), one or moregeneral purpose processors, or any combination thereof. Additionally,the one or more memory 28 may include volatile memory, such as randomaccess memory (RAM), and/or non-volatile memory, such as read-onlymemory (ROM), optical drives, hard disc drives, or solid-state drives.In some embodiments, the control unit 24 may include portions of avehicle control unit (VCU) and/or a separate battery control module.

An overhead exploded perspective view of an embodiment of the batterymodule 20 for use in the vehicle 10 of FIG. 2 is shown in FIG. 3. In theillustrated embodiment, the battery module 20 (e.g., lithium ion[Li-ion] battery module) includes a housing 30 and electrochemical cells32 disposed inside the housing 30. In the illustrated embodiment, sixprismatic lithium-ion (Li-ion) electrochemical cells 32 are disposed intwo stacks 34 within the housing 30, three electrochemical cells 32 ineach stack 34. However, in other embodiments, the battery module 20 mayinclude any number of electrochemical cells 32 (e.g., 2, 3, 4, 5, 6, 7,8, 9, 10, or more electrochemical cells), any type of electrochemicalcell 32 (e.g., Li-ion, lithium polymer, lead-acid, nickel cadmium, ornickel metal hydride, prismatic, and/or cylindrical), and anyarrangement of the electrochemical cells 32 (e.g., stacked, separated,or compartmentalized).

As shown, the electrochemical cells 32 may include terminals 36extending upwardly (e.g., in direction 37) from terminal ends 39 of theelectrochemical cells 32. Accordingly, the terminals 36 may extend intoan opening 38 disposed in an upper side 40 or face of the housing 30.For example, the electrochemical cells 32 may be inserted into thehousing 30 through the opening 38 in the upper side 40, and positionedwithin the housing 30 such that the terminals 36 of the electrochemicalcells 32 are disposed in the opening 38. A bus bar carrier 42 may bedisposed into the opening 38 and may retain bus bars 44 disposedthereon, where the bus bars 44 are configured to interface with theterminals 36 of the electrochemical cells 32. For example, the bus bars44 may interface with the terminals 36 to electrically couple adjacentelectrochemical cells 32 together. Depending on the embodiment, the busbars 44 may couple the electrochemical cells 32 in series, in parallel,or some of the electrochemical cells 32 in series and some of theelectrochemical cells 32 in parallel. Further, certain of the bus bars44 may be configured to electrically couple the electricallyinterconnected group of electrochemical cells 32 with major terminals 46of the battery module 20, where the major terminals 46 are configured tobe coupled to a load (e.g., component(s) of the vehicle 10) to power theload. The electrochemical cells 32 also include vents 49 on the terminalends 39 of the electrochemical cells 32 and configured to enable gasesfrom within the electrochemical cells 32 to vent into the inside of thehousing 30 in certain operating conditions (e.g., if a pressure withinone or more individual electrochemical cell 32 exceeds a cell ventingpressure threshold of the corresponding one or more individualelectrochemical cells 32).

In accordance with the present disclosure, the housing 30 of the batterymodule 20 includes one or more covers configured to seal the housing 30.For example, the housing 30 may include a lateral cover 50 that fitsover a lateral side 52 of the housing 30, where the lateral side 52 ofthe housing 30 retains, e.g., a printed circuit board (PCB) 52 and otherelectrical components of the battery module 20. An upper cover 54 may bedisposed over the upper side 40 of the housing 30 (and over the bus barcarrier 42) to seal the upper side 40 of the housing 30. The upper cover54 of the housing 30 may include a handle 56 embedded within the uppercover 54 and configured to facilitate transportation of the batterymodule 20 from one place to another. Further, the upper cover 54 mayinclude one or more chambers 58 configured to at least partially definea vent path of the battery module 20. Further still, the upper cover 54may include a vent spout 60 of the vent path through which gases orfluids may vent if an internal pressure within the housing 30 exceeds aventing pressure threshold of the battery module 20.

For example, an overhead perspective view of an embodiment of thebattery module 20 of FIG. 3 is shown in FIG. 4, where the chambers 58and the vent spout 60 of the upper cover 54 are illustratedtransparently for clarity. FIG. 4 also includes a cutaway portionshowing one of the electrochemical cells 32 disposed inside of thehousing 30. Gases may vent from the electrochemical cells 32 into atleast the chambers 58 of the upper cover 54 of the housing 30, where thechambers 58 define at least a portion of a vent path of the batterymodule 20. The vent path may also include an exit port 70 and the spout60 (e.g., vent spout), where the exit port 70 extends through the spout60. For example, in the illustrated embodiment, the exit port 70 extendsthrough a wall 72 of one of the chambers 58 of the upper cover 54 (e.g.,the wall 72 of the chamber 58 from which the spout 60 extends) andthrough the spout 60. It should be noted that, in another embodiment,the vent path may not include the spout 60, and the exit port 70 mayonly extend through the wall 72 of the chamber 58.

In accordance with present embodiments, a vent pad 76 (e.g., vent patch,vent label, adhesive vent label) is disposed over the exit port 70 toseal the exit port 70 from the inside of the housing 30 (e.g., to sealthe exit port 70 from the chambers 58). The vent pad 76 may be coupledto the wall 72 of the chamber 58 (e.g., an inner surface of the wall 72)via an adhesive layer. In other embodiments, the vent pad 76 may becoupled, via the adhesive layer, to other surfaces adjacent a perimeterof the exit port 70, such as an outer surface of the wall 72 of thechamber 58 or to a surface of the spout 60. The adhesive layer may beinitially disposed (e.g., before or during coupling of the vent pad 76and the wall 72 of the chamber 58) on the vent pad 76, on the innersurface of the wall 72 of the chamber 58 (e.g., along a perimeter of theexit port 70), or both.

In general, the vent pad 76 is configured to block contaminants orobjects outside of the battery module 20 from entering the housing 30,and to block gases from exiting the housing 30 through the exit port 70,unless an internal pressure within the vent path (e.g., within thechamber 58) and against the vent pad 76 exceeds a venting pressurethreshold of the battery module 20 (e.g., of the vent pad 76 of thebattery module 20). The venting pressure threshold may be calibrated byselecting or employing various characteristics of the vent pad 76, theexit port 70, the inner surface of the wall 72 to which the vent pad 76is coupled (or some other surface to which the vent pad 76 is coupled,such as the outer surface of the wall 72 or a surface of the spout 60),the adhesive layer, and/or other features of the battery module 20. Forexample, a surface area of the vent pad 76 and/or the adhesive layer,and/or a wetted surface area of the vent pad 76 (e.g., where “wettedsurface area” refers to the surface area of the vent pad 76 exposed tothe exit port 70) may be determined and employed to provide a particularventing pressure threshold. Further, a thickness of the vent pad 76and/or the adhesive layer may be determined and employed to provide aparticular venting pressure threshold. Additionally or alternatively, amaterial or texture of the vent pad 76, the adhesive layer, and/or thewall 72 or other surface on which the vent pad 76 is disposed may bedetermined and employed to provide a particular venting pressurethreshold. Further still, a pull-off strength of the adhesive layer maybe determined and employed to provide a particular venting pressurethreshold, although it should be noted that the pull-off strength of theadhesive layer may be at least in part a function of other calibrationcharacteristics described above. For example, the materials and/ortextures of the vent pad 76 and the surface to which the vent pad 76 iscoupled may establish a particular bond strength. It should also benoted that the disclosed vent path and venting features (e.g., the exitport 70, the wall 72, the vent pad 76, the adhesive layer, the ventspout 60) may be included on the upper cover 54, or on or proximate toany other suitable portion of the housing 30. These and other featureswill be described in detail below with reference to the figures.

FIG. 5 is an overhead perspective view of an embodiment of the uppercover 54 for use in the battery module 20 of FIG. 3. The upper cover 54,for clarity, is rendered transparently in the illustrated embodiment. Asshown, the chambers 58 of the upper cover 54 define at least a portionof a vent path of the battery module 20. In other words, the chambers 58may receive vented gases until a pressure within the chambers 58 (e.g.,within the vent path) and against the vent pad 76 exceeds a ventingpressure threshold of the battery module 20. For example, the vent pad76 disposed over the exit port 70 and coupled to the wall 72 (e.g., tothe inner surface of the wall 72) via the adhesive layer may be exposedto at least one of the chambers 58 such that gases within the chamber 58(e.g., within the vent path) press against the vent pad 76. If thepressure against the vent pad 76 (e.g., within the chamber(s) 58 of thevent path) exceeds the venting pressure threshold of the battery module20, the vent pad 76 may enable venting through the exit port 70.Specifically, the vent pad 76 may be configured such that a surface areaof the vent pad 76, a wetted surface area of the vent pad 76 (e.g.,exposed to the exit port 70), a strength of the adhesive layer, asurface area of the vent pad 76 coupled to the inner surface of the wall72 (or coupled to some other boundary or perimeter about the exit port70), a nature (e.g., flexibility, porosity) of the material forming thevent pad 76, etc., operate together such that the internal pressureexceeding the venting pressure threshold of the battery module 20 mayenable the vent pad 76 to pull away from the boundary or perimeter(e.g., the inner surface of the wall 72 of the chamber 58) to which thevent pad 76 is adhesively coupled, thereby exposing the exit port 70 andthe chamber(s) 58 (e.g., of the vent path) to the environment 80. Thegases vent through the exit port 70 that, in the illustrated embodiment,extends through the wall 72 and through the spout 60 (e.g., vent spout).In general, the spout 60 enables the gases to vent to an environment 80external to the battery module 20, while also protecting the vent pad 76from being torn via objects external to the housing 30 of the batterymodule 20.

It should be noted that, in accordance with present embodiments, thevent pad 76 is configured to enable venting by, in response to apressure against the vent pad 76 exceeding the venting pressurethreshold of the battery module 20, pulling away from the perimeter ofthe exit port 70 to which the vent pad 76 is adhesively coupled alongthe adhesive layer. However, in some embodiments, the vent pad 76 may beconfigured with redundancy measures in the event that the adhesive layerdoes not enable the vent pad 76 to pull away from the boundary of theexit port 70 to which the vent pad 76 is coupled. For example, the ventpad 76 may be configured to tear across a middle region of the vent pad76 in response to an internal pressure of the battery module 20 (andagainst the vent pad 76) exceeding a secondary venting pressurethreshold, which is generally greater than the venting pressurethreshold.

Further, it should be noted that any calibration features of the ventpad 76, the adhesive layer, the exit port 70, the boundary or perimeterof the exit port 70 to which the vent pad 76 is coupled, or any othercalibration features of the battery module 20 described herein withreference to calibrating the venting pressure threshold, may also bedetermined and employed to calibrate the secondary venting pressurethreshold. Indeed, in some embodiments, certain of the calibrationfeatures may be determined and employed to enable the venting pressurethreshold, and certain (other or the same) calibration features may bedetermined and employed to enable the secondary venting pressurethreshold.

Further still, in some embodiments, the vent pad 76 may be configured totear first (e.g., in response to the pressure against the vent pad 76exceeding the venting pressure threshold), and pull away from theboundary or perimeter surface of the exit port 70 in the event the ventpad 76 does not tear (e.g., in response to the pressure against the ventpad 76 exceeding the secondary pressure threshold). It should also benoted that, in some embodiments, the vent pad 76 may be configured onlyto tear and to not pull away from the boundary surface of the exit port70 along the adhesive layer 82.

FIG. 6 is a bottom perspective view of an embodiment of the cover 54 foruse in the battery module 20 of FIG. 3. In the illustrated embodiment,the vent pad 76 includes a circular cross-sectional shape, althoughother suitable shapes in accordance with the present disclosure may beincluded. The vent pad 76 is disposed over the exit port 70, which alsoincludes a circular cross-sectional shape, although other suitableshapes in accordance with the present disclosure may be included. Asshown, an annular portion of the vent pad 76 overlaps with an annularportion of the inner surface of the wall 72 of the chamber 58 in whichthe exit port 70 is disposed (e.g., the perimeter or boundary surfacearound the exit port 70). In accordance with present embodiments, theoverlapping annular portions of the vent pad 76 and the perimeter orboundary surface of the exit port 70 may include an adhesive layer 82disposed therebetween. The adhesive layer 82 may be initially disposedon the vent pad 76, on the perimeter of the exit port 70 (e.g., on theinner surface of the wall 72), or both, and may operate to retain thevent pad 76 over the exit port 70. In some embodiments, the vent pad 76may pull away from the wall 72 along the adhesive layer 82 if thepressure against the vent pad 76 (and, thus, within the vent path, orwithin the chamber(s) 58) exceeds the venting pressure threshold of thebattery module 20. For example, the vent pad 76 and the adhesive layer82 may separate from the wall 72 to enable gases to vent through theexit port 70. As previously described, the vent pad 76 (and/or otherventing features) may be configured such that the vent pad 76 tearsthrough a middle region if the internal pressure within the chamber 58(and against the vent pad 76) exceeds the secondary venting pressurethreshold of the battery module 20. The secondary venting pressurethreshold is greater than the venting pressure threshold, where theventing pressure threshold, as previously described, is calibrated toenable the vent pad 76 to pull away from the wall 72 along the adhesivelayer 82.

A cross-sectional view of an embodiment of the vent pad 76 disposed in aportion of the vent path is shown in FIG. 7. As previously described, anouter annular portion 90 of the vent pad 76 may overlap with an annularportion 92 of perimeter or boundary surface of the exit port 70 (e.g.,along an inner surface 97 of the wall 72 of the chamber 58 and aroundthe exit port 70). The vent pad 76 may be coupled at the outer annularportion 90 to the annular portion 92 of the inner surface 97 of the wall72 via the adhesive layer 82. As shown, the adhesive layer 82 maysubstantially cover the entire outer annular portion 90 of the vent pad76 that overlaps with the annular portion 92 of the inner surface 97 ofthe wall 72.

It should be noted that the vent pad 76 may be coupled to a differentsurface of the upper cover 54, or a different surface of the batterymodule 20. For example, the vent pad 76 may be coupled, via the adhesivelayer 82, to an end surface 99 of the spout 60. Further, in embodimentsnot having the spout 60, the vent pad 76 may be coupled, via theadhesive layer 82, to an outer surface 101 of the wall 70 opposite tothe inner surface 97. In general, the vent pad 76 may be coupled to asurface proximate an entrance 102 to the exit port 70 or proximate to anexit 105 of the exit port 70. As shown, the entrance 102 in theillustrated embodiment is even with the inner surface 97 of the wall 72(e.g., in direction 107), and the exit 105 is even with an end of thespout 60 (e.g., in direction 107). However, in embodiments not havingthe spout 60, the exit 105 may be even with the outer surface 101 of thewall 72 (e.g., in direction 107) or even with some other surface of theupper cover 54 or battery module 20.

In other embodiments, the adhesive layer 82 may only be applied betweena portion of the outer annular portion 90 of the vent pad 76 and theannular portion 92 of the inner wall 72. Indeed, such controlledapplication may be used for calibration purposes. For example, more orless surface area may include adhesive to increase or lessen the ventingpressure threshold (e.g. relief threshold), respectively. A front viewof an embodiment of the vent pad 76 covering the exit port 70 is shownin FIG. 8. In the illustrated embodiment, the adhesive layer 82 isarcuate with a radial width 100 equal to that of the overlapping annularportions 90, 92 of the vent pad 76 and the boundary surface of the exitport 70, respectively. However, the radial width 100 of the adhesivelayer 82 may be smaller or larger than that of the overlapping annularportions 90, 92 based on calibration preference. The adhesive layer 82may additionally (or alternatively) extend less than 360 degrees aroundthe exit port 70. For example, the adhesive layer 82 may includemultiple arcuate strips 104 (e.g., two or more arcuate strips 104) ofless than 360 degrees arranged about the exit port 70 and between theoverlapping annular portions 90, 92 of the vent pad 76 and the boundarysurface of the exit port 70 (e.g., the wall 72 of the chamber 58),respectively. Further, as shown in the illustrated embodiment, the ventpad 76 may include a kiss-cut 113 or score grooved into the vent pad 76to facilitate tearing of the vent pad 76 in response to the internalpressure within the vent path exceeding the secondary venting pressurethreshold of the battery module 20, as previously described.

In general, the vent pad 76, the adhesive layer 82, the wall 72 (orother boundary or perimeter surface of the exit port 70), and the exitport 70 may be designed to calibrate the venting pressure threshold, inaccordance with present embodiments, such that venting through the exitport 70 is enabled when an internal pressure within the vent path (e.g.,within the chamber 58) and against the vent pad 76 exceeds the ventingpressure threshold. For example, a particular surface texture of theboundary surface of the exit port 70, of the vent pad 76, of theadhesive layer 82, or a combination thereof may be specifically includedto calibrate the venting pressure threshold of the battery module 20.Further, a particular thickness of the adhesive layer 82, thickness ofthe vent pad 76, thickness of the wall 72, surface area of the adhesivelayer 82, wetted surface area of the vent pad 76, surface area of thevent pad 76, overlapping surface areas of the vent pad 76 and theboundary surface to the exit port 70, or a combination thereof may bespecifically included to calibrate the venting pressure threshold(and/or the secondary venting pressure threshold) of the battery module20. Further still, a particular material of the adhesive layer 82,material of the vent pad 76, material of the boundary surface of theexit port 70, pull-off strength of the adhesive layer 82 (which maycorrespond with materials and/or textures of the vent pad 76, theadhesive layer 82, the boundary surface to the exit port 70, etc.), or acombination thereof may be specifically included to calibrate theventing pressure threshold (and/or the secondary venting pressurethreshold) of the battery module 20. In embodiments including multiplestrips 104 of the adhesive layer 82, a particular number of the strips104, a number of arcuate degrees per strip 104, other characteristics(e.g., thickness) or a combination thereof may be specifically includedto calibrate the venting pressure threshold of the battery module 20.Further, to enable venting through the exit port 70, the vent pad 76 maybe designed to pull away from the surface to which the vent pad 76 iscoupled via the adhesive layer 82 (e.g., the wall 72 of the exit port70) along the adhesive layer 82. In some embodiments, as previouslydescribed, the vent pad 76 may be designed to tear through a middleregion 103 of the vent pad 76. It should be noted that the vent pad 76may flex to an extent, by design, before pulling away from the boundarysurface of the exit port 70 (e.g., the boundary surface extending alongthe wall 72). Certain of the venting calibration features describedabove may be specifically included to determine the one or more of thepressure thresholds for various venting modes (e.g., pull-away mode ortear mode) of the vent pad 76.

It should be noted that, in accordance with present embodiments, thedisclosed vent pad 76, exit port 70, adhesive layer 82, and vent pathmay be included in any suitable area of the battery module 20 or housing30 of the battery module 20. The embodiments and correspondingdescriptions of the venting features with respect to the upper cover 54are non-limiting.

Further, it should be noted that, in other embodiments, additionalfeatures may be included that enable the vent pad 76 to allow ventingthrough the exit port 70. For example, cross-sectional side views ofembodiments of the vent path (e.g., having the vent pad 76 disposedtherein) are shown in FIGS. 9 and 10. In the illustrated embodiments, asharp edge 106 is disposed a first distance 120 from the vent pad 76.The distance 120 may be specifically determined and employed forcalibrating the venting pressure threshold of the battery module 20. Inthe embodiment shown in FIG. 9, the sharp edge 106 extends from asurface 108 within the spout 60. In the embodiment shown in FIG. 10, thesharp edge 106 is disposed within a loosely arranged bubble 109 disposedon (e.g., coupled to) the vent pad 76. For example, the bubble 109 iscoupled or connected to the vent pad 76 along a connecting edge of thebubble 109. A rise in pressure within the vent path (e.g., within thechamber 58 of, or proximate to, the exit port 70) and against the ventpad 76 may cause the vent pad 76 to deflect or flex outwardly (e.g., indirection 107, as indicated by deflection 111 in FIG. 9) toward thesharp edge 106. As the vent pad 76 flexes outwardly, the connecting edgeof the bubble 109 remains fixed to the vent pad 76. Thus, the bubble 109becomes more and more taut, until the sharp edge 106 contacts the ventpad 76. The amount of deflection 111, which may be a property of thematerial or elasticity of the vent pad 76, may be specificallydetermined and employed for calibration of the venting pressurethreshold of the battery module 20. It should also be noted that thebubble 109 in FIG. 10 may be coupled to the vent pad 76 along theconnecting edge while the bobble 109 is in a relaxed condition duringnormal operating conditions, and while the vent pad 76 may be in a tautcondition. Thus, the vent pad 76 may deflect or flex outwardly (e.g., indirection 107) more so than the bubble 109 (which is fixed to the ventpad 76 along the connecting edge) as the bubble 109 becomes increasinglymore taut, thereby enabling the sharp edge 106 coupled to the bubble 109to contact and open the vent pad 76, enabling venting through the exitport 70). Further, it should be noted that, in embodiments including thesharp edge 106, the vent pad 76 may be coupled to the boundary surfaceof the exit port 70 (e.g., to the wall 72 of the chamber 58) via someother coupling mechanism. It should also be noted that the vent pad 76may include the kiss-cut 113 shown in FIG. 8, and that the sharp edge106 may contact the grooves of the kiss-cut 113 to open the vent pad 76.It should also be noted that any number of sharp edges 106 may beincluded to facilitate opening of the vent pad 76, and that locations ofthe one or more sharp edges 106 (e.g., proximate a center of the ventpad 76, a perimeter of the vent pad 76, or anywhere else along the ventpad 76) may be determined and employed to calibrate the venting pressurethreshold of the battery module 20.

Turning now to FIG. 11, a schematic view of an embodiment of a portionof a vent path 120 for use in the battery module 20 of the vehicle 10 ofFIG. 2 is shown. In the illustrated embodiment, the vent path 120includes the exit port 70 extending through at least the spout 60 andthe wall 72 (e.g., any wall of the battery module). In otherembodiments, the vent path 120 may not include the spout 60. As shown,multiple vent pads 76 may be disposed in various locations along thevent path 120. For example, one vent pad 76 may be coupled to the wall72 (via the adhesive layer 82) over the entrance 102 to the exit port70. A different vent pad 76 may be coupled to the wall 72 (via theadhesive layer 82) on a different surface of the wall 72, such as exitsurface 112 of the wall 72. Further, a different vent pad 76 may bedisposed over an exit of the exit port 70 (e.g., coupled via theadhesive layer 82 to the end surface 99 of the spout 60. It should benoted that any combination of the illustrated vent pads 76 may beincluded, in accordance with present embodiments, including only one ofthe illustrated vent pads 76. Further, any of the aforementioned ventfeatures (e.g., the sharp edge 106, the bubble 109, the kiss cut 113)may be included. As previously described, if the internal pressurewithin the battery module 20 and against any of the vent pads 76 exceedsthe venting pressure threshold of, for example, the vent pad 76, thevent pad(s) 76 in question may enable venting through at least theportion of the exit port 70 sealed by the vent pad 76. It should benoted that the vent path 110 (e.g., the exit port 70, the vent pad 76disposed in the vent path 110, the adhesive layer 82, and, depending onthe embodiment, other features of the battery module 20) may be locatedin any suitable are of the battery module. Further, as previouslydescribed, the vent pad 76, the exit port 70, the adhesive layer 82, andother features of the battery module 20 may include characteristicsspecifically determined for calibrating the venting pressure thresholdof the battery module 20, as discussed above.

One or more of the disclosed embodiments, alone or in combination, mayprovide one or more technical effects useful in the manufacture ofbattery modules, and portions of battery modules. In general,embodiments of the present disclosure include a vent path having an exitport and a vent pad disposed over the exit port. An adhesive layer isdisposed between the vent pad and a boundary or perimeter surface of theexit port. In accordance with present embodiments, the vent pad, theexit port, the boundary or perimeter surface of the exit port, theadhesive layer, and/or other features or components of the batterymodule may be designed to calibrate a venting pressure threshold of thebattery module. In other words, characteristics of the vent pad, theexit port, the boundary or perimeter surface of the exit port, theadhesive layer, and/or the other features or components of the batterymodule may be included such that the vent pad enables venting throughthe exit port if a pressure inside the vent path (and against the ventpad) exceeds the venting pressure threshold. This provides a tunable andeconomic vent control feature. Also, certain characteristics such asporosity and flexibility may be utilized for calibration. The technicaleffects and technical problems in the specification are exemplary andare not limiting. It should be noted that the embodiments described inthe specification may have other technical effects and can solve othertechnical problems.

While only certain features and embodiments have been illustrated anddescribed, many modifications and changes may occur to those skilled inthe art (e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters (e.g.,temperatures, pressures, etc.), mounting arrangements, use of materials,colors, orientations, etc.) without materially departing from the novelteachings and advantages of the disclosed subject matter. The order orsequence of any process or method steps may be varied or re-sequencedaccording to alternative embodiments. Furthermore, in an effort toprovide a concise description of the exemplary embodiments, all featuresof an actual implementation may not have been described. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerous implementationspecific decisions may be made. Such a development effort might becomplex and time consuming, but would nevertheless be a routineundertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure, without undueexperimentation.

1. A battery module, comprising: a vent path having an exit port; a ventpad disposed within the vent path and blocking at least a portion of theexit port, coupled to a boundary surface of the exit port via anadhesive layer between the vent pad and the boundary surface, andconfigured to enable venting through the exit port by separating fromthe boundary surface along the adhesive layer in response to a pressureagainst the vent pad exceeding a venting pressure threshold of thebattery module.
 2. The battery module of claim 1, wherein the adhesivelayer fully encircles the exit port.
 3. The battery module of claim 1,wherein the venting pressure threshold of the battery module iscalibrated by including one or more venting calibration features of thebattery module.
 4. The battery module of claim 3, wherein at least oneof the one or more venting calibration features comprises a surfacetexture of the exit port, a surface texture of the vent pad, a surfacetexture of the adhesive layer, or a combination thereof.
 5. The batterymodule of claim 3, wherein at least one of the one or more ventingcalibration features comprises a thickness of the adhesive layer, athickness of the vent pad, a surface area of the adhesive layer, asurface area of the vent pad, a wetted surface area of the vent pad, anoverlapping surface area of the vent pad and the boundary layer of theexit port, or a combination thereof.
 6. The battery module of claim 3,wherein at least one of the one or more calibration features comprises amaterial of the adhesive layer, a material of the vent pad, a materialof the boundary surface of the exit port, or a combination thereof. 7.The battery module of claim 3, wherein at least one of the one or morecalibration features comprises a pull-off strength of the adhesivelayer.
 8. The battery module of claim 1, comprising a plurality ofelectrochemical cells disposed within a housing, wherein the vent pathis at least partially defined by the housing and the exit port extendsthrough a portion of the housing, wherein the plurality ofelectrochemical cells is disposed within the housing, and wherein theplurality of electrochemical cells is a plurality of prismaticlithium-ion (Li-ion) electrochemical cells.
 9. The battery module ofclaim 1, comprising at least one sharp edge disposed proximate to thevent pad, wherein the vent pad is configured to flex into the at leastone sharp edge in response to the pressure against the vent padexceeding the venting pressure threshold of the battery module, therebycausing the at least one sharp edge to tear the vent pad.
 10. Thebattery module of claim 9, wherein the vent pad comprises a pouch orbubble and the at least one sharp edge is disposed in the pouch orbubble.
 11. The battery module of claim 1, wherein the vent padcomprises a score or kiss-cut.
 12. The battery module of claim 1,comprising a vent spout through which at least a portion of the exitport extends, wherein the vent spout comprises an end extending into anenvironment external to the battery module, wherein the vent spout isconfigured to protect the vent pad from contaminants and/or objectsexternal to the vent path.
 13. The battery module of claim 1,comprising: a plurality of electrochemical cells; a housing configuredto receive the plurality of electrochemical cells through an opening inthe housing; and a cover disposed over the opening in the housing,wherein the exit port extends through a wall of the cover.
 14. Thebattery module of claim 1, wherein the vent pad is configured to tear inresponse to the pressure against the vent pad exceeding a secondaryventing pressure threshold of the battery module and the secondaryventing pressure threshold of the battery module is greater than theventing pressure threshold of the battery module.
 15. The battery moduleof claim 1, wherein the vent pad is disposed on the boundary surface ofthe exit port proximate to an entrance to the exit port or proximate toan exit of the exit port.
 16. A housing of a battery module, comprising:a cover disposed over an opening in the housing; a vent path having anexit port disposed through a wall of the cover; and a vent pad blockingthe exit port, coupled to a surface of the wall of the cover via anadhesive layer between the vent pad and the surface of the wall, andconfigured to enable venting through the exit port in response to apressure within the vent path and against the vent pad exceeding apressure threshold of the battery module.
 17. The housing of claim 16,wherein the vent pad is configured to enable venting through the exitport by tearing through a middle region of the vent pad in response tothe pressure within the vent path and against the vent pad exceeding thepressure threshold.
 18. The housing of claim 16, wherein the vent pad isconfigured to enable venting through the exit port by separating fromthe surface of the cover along the adhesive layer in response to thepressure within the vent path and against the vent pad exceeding thepressure threshold.
 19. The battery module of claim 16, wherein thepressure threshold is calibrated by controlling one or more ventingcalibration features, wherein at least one of the one or more ventingcalibration features comprises a surface texture of the wall of thecover, a surface texture of the vent pad, a surface texture of theadhesive layer, a thickness of the adhesive layer, a thickness of thevent pad, a surface area of the adhesive layer, a surface area of thevent pad, a wetted surface area of the vent pad, a material of theadhesive layer, a material of the vent pad, a material of the wall, apull-off strength of the adhesive layer or vent pad, or a combinationthereof.
 20. The battery module of claim 16, comprising a plurality ofprismatic lithium-ion (Li-ion) electrochemical cells disposed within thehousing.
 21. The battery module of claim 16, comprising at least onesharp edge disposed proximate to the vent pad, wherein the vent pad isconfigured to enable venting through the exit port by deflecting orflexing into the at least one sharp edge in response to the pressurewithin the vent path and against the vent pad exceeding the ventingpressure of the battery module, thereby causing the at least one sharpedge to tear the vent pad.
 22. A battery module, comprising: a vent pathand an exit port of the vent path; a vent pad coupled to a first surfaceof the battery module through which the exit port extends and disposedover the vent opening; and a sharp edge facing the vent pad a firstdistance from a resting position of the vent pad, wherein the vent padis configured to deflect from the resting position at least the firstdistance in response to a pressure within the vent path and against thevent pad exceeding a venting pressure threshold of the battery module,such that the sharp edge contacts and opens the vent pad to enableventing through the vent opening.
 23. The battery module of claim 22,wherein the vent pad comprises a kiss-cut or score.